1. Field of the Invention
The present invention relates to a noise absorbing device of a vacuum cleaner, and more particularly to a noise absorbing device of a vacuum cleaner of which efficiency for absorbing noise is increased due to an extended exhaust air flow path.
2. Description of the Prior Art
In the prior art, several types of noise absorbing devices for vacuum cleaners have been proposed and widely used.
For example, Japanese U.M. Publication No. Sho. 62-45631 (applied on Oct. 23, 1981 and published on Dec. 7, 1987) discloses a noise absorbing device of a vacuum cleaner which is shown in FIG. 1 of the accompanying drawings.
As shown in FIG. 1, the conventional vacuum cleaner comprises a suction motor 2 provided in a cleaner housing 1. In FIG. 1, the suction motor 2 is connected with a suction port 8. The air is exhausted to the rear portion of the suction motor 2 through the suction port 8. The exhaust port provided on the back of the housing 1 for exhausting the purified air to the outside is denoted by the numeral 3. The suction motor 2 for generating suction force communicates with the exhaust port 3 through both an air path 4 and an exhaust silencer 5. The exhaust silencer 5 defines an exhaust path 6 therein. In the above noise absorbing device, the exhaust path 6 of the exhaust silencer 5 is inclined upwardly from an air path 4 at an obtuse angle. With the inclined relationship between the exhaust path 6 and air path 4 of the housing 1, it is possible to suppress the turbulence noise caused by the exhaust air flow having already passed through the suction motor 2. In the above silencing device, the turbulence noise is partly absorbed and suppressed by a noise absorbing material 7.
However, the above noise absorbing device for a vacuum cleaner, while partly absorbing and suppressing the exhaust noise caused by exhaust air flow having passed through the suction motor 2, nevertheless has a problem that the exhaust air flow should pass through a relatively short path and be exhausted to the outside of the housing 1, so that it is impossible to achieve the desired noise absorbing and suppressing effect.
Moreover, the exhaust air passing through the suction motor 2 is exhausted not through a filter but directly through a chink of the assembled part of the housing 1 to the outside, which causes efficiency of the cleaning working to deteriorate.